The present invention is related to dispensing devices for aerosols and in particular to a metering valve for delivering metered quantities of an aerosol composition.
Aerosol compositions generally are of two kinds, namely those in which the composition contains a propellant liquid which vaporizes very rapidly when the composition is at atmospheric pressure, and those in which the propulsion of the aerosol composition is effected by maintaining the liquid composition in a container under the pressure of a permanent gas, such as nitrogen.
The term "aerosol composition" as employed herein includes compositions other than simple liquids such as pastes which may be discharged in the form of a coherent ribbon or stream, and viscous liquids which may be discharged in the form of a jet or a series of large drops and is not limited to compositions which are discharged in the form of the very minute droplets normally referred to as aerosols in the art to which the present invention relates.
Usually, the discharge tube will be provided with an actuator in the form of a nozzle member so constructed as to discharge the aerosol composition in the form of a jet, spray, or ribbon and to provide a conveniently shaped end part to which manual pressure can be applied to operate the valve.
Various prior constructions have been proposed for dispensing of metered quantities of aerosol compositions. Typical of such structures are those contained in U.S. Pat. Nos. 3,176,887; 3,058,629; 2,968,427; 2,933,222; 2,856,103; and 2,788,925 which illustrate various metering valves of the prior art.